1. Field of the Invention
Various embodiments of the present invention relate to pre-jam waveforms for enhanced optical break lock jamming effects.
In various examples, pre-jam waveforms for enhanced optical break lock jamming effects may be implemented in the context of systems, methods, computer program products and/or algorithms.
2. Description of Related Art
Infrared (IR) guided surface-to-air missiles typically work by detecting emitted IR radiation from a target. IR energy is collected by a spinning gyroscopic telescope and is modulated by a complex reticle. This modulated energy is collected by an IR sensitive detector and used to generate a time-varying electrical signal. This signal has features (e.g., amplitude and/or frequency) which are proportional to the pointing error angle between the gyroscopic telescope and the target in question.
The detected signal is typically processed through two electrical control loops. The first loop is commonly referred to as the “track” loop and is used to maintain the pointing of the gyroscopic telescope. The track loop acts to reduce the measured error angle between the telescope and the target. The second loop is commonly referred to as the “guidance” loop and is used to maintain the pointing of the missile body. The guidance loop acts to steer the missile body to a predicted intercept point based on the perceived target motion.
In the employment of directable IR laser countermeasures, a laser is aimed into the missile's gyroscopic telescope and the laser light is modulated in such a way as to emulate the error signal of the missile. Using a higher laser power and stray-light paths, the laser light is able to generate a more powerful signal than the true error signal associated with the target. This countermeasure signal is used to steer the missile's gyroscopic telescope to a position where the gyroscopic telescope can no longer see the target. A missile which has been commanded to look at a position other than the target is said to be in a condition of optical break lock (“OBL”). OBL is typically the primary defeat mechanism for modern laser jammers and frequencies.
A problem with OBL is that it is typically an insufficient metric to determine the success of an IR engagement. A missile which is not looking at the target may still hit the target given the ballistic path of the missile, especially if countermeasures are deployed late in the engagement and/or no evasive maneuvers are employed by the target. Frequencies in modern jam codes are generally optimized for OBL. Design of a missile is generally such that the missile track loop can respond at rates up to 10 times the guidance loop. Although modern OBL codes typically do generate some motion in the missile guidance loop, this motion is significantly attenuated relative to the motion in the track loop. Frequencies in modern OBL codes are typically selected based on the “spin” frequency of the missile. That is, the frequencies used are selected to match the best guess of the current spin rate of the missile's telescope. This produces straight line motion from the missile head and generates the fastest OBL possible.
FIG. 1 shows a block diagram of a conventional interaction between an IR seeking missile and a countermeasure system installed on a target. As seen in this figure, missile 101 includes seeker head 101A (having therein a spinning gyroscopic telescope). The seeker head 101A detects emitted IR radiation from a target 103 (e.g., an aircraft or the like). Further, countermeasure system 105 includes laser 105A, which sends laser light (not necessarily visible) to the missile's gyroscopic telescope.